The present invention relates to keyboard operated computing systems. Specifically, an apparatus is described which supports a control function such as a pointing function typically performed by an auxiliary device to be integrated into a keyboard. This device is actuated by exerting a lateral force on the surface of the keyboard key tops.
Keyboard operated computing systems have supported rapid entry of alpha numeric data by providing an efficient tool for this operation to data entry personnel. Computer operations in a graphical environment provided by some computing systems are advantageously manipulated by auxiliary pointing devices which are used to move a cursor from one location on a display to another. In such environment, pointing devices such as "mice" permit screen displayed objects to be identified for some subsequent operation.
The combined use of keyboard data entry systems and pointing devices introduce some inefficiency since the user is required to move his hands from the typing position to a remote, printing-device-operating position. If many pointing operations are required, the interruption to typing operations seriously degrades the data input efficiency of the keyboard.
One approach to making the pointing function more efficient has been to introduce more keys to the keyboard which can be used for cursor manipulation. This uses keyboard space at the expense of implementing other functions. Even with additional keys (usually located on the right side of the keyboard) the keyboard operator is required to remove one hand from the "home" position when shifting from a keystroke operation to a pointing operation, thus reducing typing efficiency.
Incorporation of mouse control features in keyboard devices has been described in various references. In publications entitled "Mouse/Keyboard Concept Incorporating Unique Devices For Control CRT Display Cursors", IBM TDB, Vol. 27, No. 103, March 1985, and "An Integrated Mouse and Keyboard" IBM TDB, Vol. 31, No. 8, January 1989, page 230, the implementation of a mouse on the underside of the base of the keyboard is suggested. Movement of the keyboard over a supporting surface could then be encoded into mouse signals for positioning a cursor. This approach, however, has numerous disadvantages. Among these are a requirement for a larger work space to accommodate movement of the keyboard in four coordinate directions. Additionally, moving the keyboard is physically demanding, and when moved, the keyboard is no longer optimally placed for typing.
U.S. Pat. No. 4,680,577 describes a keyboard which provides at least one key which may be rocked or flexed laterally in addition to being depressed as a conventional keystroke. The rocking motion is encoded to position a cursor on a CRT. The patent suggests the key implementation for two of the "home" keys, such as F or J. The additional problem of emulating mouse buttons is not addressed by this patent, nor is that of inadvertent depression of the pointing key, nor is that of pointing when no finger is on either of these keys.